Rotary printing cylinder



May 3, 1932. H. BURKHOLDT ROTARY PRINTI NG CYLINDER Filed March 27, 1951 2 sheets-sheet 1 May'B, 1932. H. BURKHOLDT ROTARY PRINTING CYLINDER Filed March 27, 1931 2 Sheets-Sheet 2 lift Patented May 3, 1932 UNITED STATES PATENT OFFICE HERBERT IB'U'RKHOLDT, 0F STETTIN, GERMANY, ASSIGNOR TO THE FIRM OF CARL BEAVER, G. "M. B. H., 0F STE'ITIN', GERMANY, A JOINT-STOCK COMPANY OF GERMANY ROTARY rain-Tins c'yninnna Application. filed March 27, 1931, Serial No. 525,808, and in Germany April 9, 1930.

My invention relates to improvements in rotary printin cylinders, and more particularly in cylind ers adapted to have a stencil placed thereon, and provided with internal inking means. The object of the improvernents is to provide a printing cylinder of this type in which the ink is uniformly supplied through the circumferential wall of the cylinder. With this object in view my invention consists in disposing a cylinder concentrically within the printing cylinder and providing an annular receptacle which has an equal radial dimension all over its length. Therefore, when the cylinder rolls on the sheet of paper or the like the ink within the inking chamber is always under uni form pressure, the said pressure corresponding to the said radial dimension of the inking chamber, and by thus holding the ink under a uniform pressure the flow thereof through the cylindrical wall is uniform.

it has heretofore been proposed, for instance, to provide an ink holder which is suspended on the interior of the drum, the ink eing permitted to drip through apertures in the holder. @bviously this does not result in uniform distribution of the ink about the drum. It has also been proposed to fill the interior of the drum with ink but in this case the drum obviously varies materially in weight according to the quantity of ink int-roduced. As the center of gravity of the liquid when the drum is partially filled, as under ordinary operating conditions, lies below the center of rotation of the drum, this liquid is subjected to considerable oscillation and consequent alteration of position during printing and the pressure exerted by the l1qu1d at various oints on the drum also varies. lhus the a sorbent surface cannot be uniformly impregnated with the liquid and irre ular printing inevitably results.

e present arrangement not only ensures substantially equal pressure of liquid at all points on the drum, but as the result of the small amount of liquid used the amplitude of oscillation of the liquid on rotation of the drum is considerably lessened. Thus uniform moistening of the absorbent surface can be obtained.

In machines of this type the flow of the ink through the perforations of the printing cylinder is controlled by means of an annular slide which is formed with perforations corresponding to the perforations of the cylw consists in providing the said annular slide a at its meeting ends with bands adapted to be put under tension or shifted in one or the other directions'circumferentially of the cylinder by means of a suitable gearing from the outside of the cylinder, the said slide being adapted to be brought with its perforations in register with the perforations of the cylinder or into position for closing the said perforations. Preferably, the handle for operating the said gearing is located at one of the end faces of the cylinder where it is readily accessible, and the end ositions of the said handle are determined y stops indicating the opening and closing position of the slide. Therefore the slide may be set into the desired position by non-skilled persons. In connection with the said handle scale marks may be provided for indicating intermediate positions'of the handle.

For the purpose of explaining the invention an example embodying the same has been shown in thelgiaccompanying drawings, in which the same/letters of reference have been used in all the views to indicate corresponding parts; in said drawings,

Fig. 1 is a top plan view of the printing cylinder,

Fig. 2 is a fragmentary end view showing the handle for operating the slide controlling the flow of the ink through the cylinder, and Figs. 3 and 4 are sectional elevations taken on the line 3--3 of Fig. 1 and showing the parts of the slide controlling mechanism in different positions, Fig. 4 also showing the manner of securing the inking pad and the stencil in position.

In the example shown in the figures the printing cylinder comprises a perforated cylinder or sieve 6 having an inking wheel 6 trained thereon, the stencil n being trained portion 9 the dimensions of which are shown in Fig. 1. Preferably, the perforations of the drum 6 are not provided all over the surface thereof, but at such parts where usually the stencil n does not display letters, drawings, and the like the drum is made solid, as is shown at e and 6 The cut-out portion 9 is adapted to be closed by means of a lid 9' adapted to be fixed in position by means of screws 2;

Within the cylinder 6 there is an ink con- 15 tainer a which as shown is provided by an outer cylinder at and an internal concentric cylinder 1 the said cylinders d and 1' being fixed tothe end walls 0 and c and being closed at their open ends 'by walls at and d The cylinder (1 is provided with perforations corresponding in position to the perforations of the outer cylinder 0.

Between the cylinders (Z and 6 there is a cylindrical slide f of sheet metal which is formed with perforations corresponding in size and position to the perforations of the cylinders 01 and e. The adjacent ends of the slidef are equipped with ears 7 and P, which are secured by screws, by soldering, welding, "or the like to bands h. In the construction shown in Fig. 1 two bands 72. are provided which-are disposed transversely of the cutout portion 9, and which are formed with longitudinal slots 1: and '0 separated from eachother bya bridge 25.

Longitudinally of the cylinder and away from-the axis-thereof a shaft Z is provided to the outer end of which a crank 0 is secured. At the rear of the said crank there is a se mental rail which is provided with sea e marks 9 anithe end positions of the crank are determined by stops m and '3 Within the cylinder two cam disks k are fixed to the shaft J Z, which cam disks are located internally of -the cut-out portion g. To each cam disk 3. lug and two pins m and m are fixed. By turning the shaft Z in one or the other direction the said pins engage in the slots 1)? or v of the bands h when the crank o is neaiffits' end'positions. For example, for opening the slide f is slightly turned in clockwise direction before the crank arrives in the end position shown inFig. 2. When the crank is in thesaid position the slide f is in position for closing the perforations of the cylinders d and e.

' Fig. 3 shows an intermediate position of the slide. The lug k bears on the bridge t and it puts the band h under tension. Thereby the position of the slide f is not changed, as is shown in Fig. 3, in which the crank 0 is understood to have been turned in anticlockwise direction and out of the position in which the slide f closes the cylinders d, e. Therefore the slide f still closes the inking chamber a, so that no ink can pass through the cylinders 03, e. But when the slide f opens the perforations of the said cylinders ink passes through the said perforations and to the inking pad from whence'it passes through the stencil n, as is known in the art.

With one of its ends the inking pad bis clamped below a rockable rail u to which the stencil is secured, and with its opposite end it is clamped in position by means of a rail w, the said rail also holding the inking pad 6. The rail is fixed in position by means of screws w While in describing the invention reference has been made to a particular example embodying the same I Wish it to be understood that my invention is not limited to the con: struction shown in the drawings, and that various changes may be made in the general arrangement of the apparatus and the construction of its parts, without departing from the invention.

I claim:

1. A printing cylinder, comprising a permeable cylindrical wall, means for placing a stencil on said permeable wall, and an annular'inking chamber within said cylinder comprising an outer cylinder adjacent to said permeable wall and formed with perforations and an inner concentric cylinder.

2. A printing cylinder having a permeable wall, means for attaching a stencil to said permeable wall, an ink container within said permeable wall and comprising a concentric cylinder formed with perforations, a cylinperforations f th cylinder e the in m is ,dIlCal slide between said permeable wall and turned into position for engaging the slot '0 and near the end of its movement and before the crank o'bears on the stop a: it has engaged the right hand edge of the bridge t cylinder and formed with perforations corresponding to the perforations of said cylinder, and means for shifting said slide relatively to the cylinder for opening and closing separating the slots '0 and o? from each other, he p rforations thereof.

andit has shifted the slide f in anti-clockwise direction and into position for bringing ll, means for attaching a stencil to said the perforations of the slide into register with the perforations'of the cylinders d and e, as is shown in Fig. 4. When turning the shaft 1 in opposite direction the pin on is brought into engagement with the slots '0 of the bands h. and into contact with the 3. A printing cyli der having a permeable permeable wall, end walls, an ink container within said permeable wall and com rising a concentric cylinder formed with per orations,

a cylindrical slide between said permeable wall and cylinder and formed with perforations corresponding to the perforations of "left hand edge of the bridge t, so that the said cylinder, a shaft within said cylinder parallel to the axis thereof and extending i through one of the end walls of said cylinder, operating means connected with the outer end of said shaft, and an operative connection between said slide and shaft.

4. A printing cylinder having a permeable wall and formed with a longitudinal cut-out portion, means for mounting a stencil on said wall, an inking chamber within said cylinder comprising a concentric cylinder formed with perforations and having a cut-out portionv corresponding in position to said cut-out po rtion of the outer wall, a slide between sald permeable wall and said concentric cylinder and formed with perforations corresponding in position to the perforations of said concentric cylinder, said slide having a cut-out portion, means for mounting a stencil on said wall, an inking chamber within said cylinder comprising a concentric cylinder formed with perforations and having a cutout portion corresponding in position to sald cut-out portion of the outer wall, a slide between said permeable wall and said concentric cylinder and formed with perforations corresponding in position to the perforations of said concentric cylinder, said slide having a cut-out portion corresponding to the cutout portions of said permeable wall and said concentric cylinder, bands connecting the open ends of said slide and each formed with slots separated from each other by abridge, a shaft disposed longitudinally of said concentric cylinder,.pairs of pins connected to said shaft andlocated in position for engaging said slots and bridge and adapted when said shaft is rocked to shift said slide in circumferential direction for opening and closing the perforations of said concentric cylinder, and means located at the outside of said cylinder for rocking said shaft.

b. A printing cylinder having a permeable wall and formed with a longitudinal cutout portion, means for mounting a stencil on said wall, an inking chamber within said cylinder comprising a concentric cylinder formed with perforations and having a cutout portion corresponding in position to said cut-out portion of the outer wall, a slide between said permeable wall and said concen trio cylinder and formed with perforations corresponding inposition to the perforations of said concentric cylinder, said slide having a cut-out portion corresponding to the cutout portions of said permeable wall and said concentric cylinder,bands connectingthe open ends of said slide and each formed with slots separated from each other by a bridge, a

shaft disposed longitudinally of said cylinder, pairs of pins connected to said shaft and located in position for engaging said slots and bridge and adapted when said shaft is rocked to shift said'slide in circumferential direction for opening and closing the perforations of said concentric cylinder, lugs on said shaft one for each of said bands and adapted when said shaft is rocked to engage said bands for putting the same under tension, the lengths of said slots being such that said lugs engage the bands while the pins are out of contact with said bridges, and means located at the outside of said cylinder for rocking said shaft.

7. A printing cylinder having a permeable Wall and formed with a longitudinal cutout portion, means i for mounting a stencil on said wall, an inking chamber within said cylinder comprising a concentric cylinder formed with perforations and having a cutout portion corresp'onding'in position to said cut-out portion of the outer wall, a slide between said permeable wall and said con-' centric cylinder and formed with perforations corres onding in position to the perforations 0 said concentric cylinder, said slide having a cut-out portion corresponding to the cut-out portions of said permeable wall and said concentric cylinder, bands connecting the open ends of said slide and each formed with slots separated from each other by a bridge, a shaft disposed longitudinall of said cylinder, disks secured to said sha t one for each of said bands, pairs of pins fixed to said disks in positions for engaging said slots and bridges, lugs secured to said disks-and located in position for engaging the inner faces of said bands and for putting the same under tension,- the. lengths of said slots 'beingsuch that the lugs engage the bands wh1le the slots are out of contact with said bridges, and means for turning said shaft from without.

8. A printing cylinder having a permeable I wall, means for mounting a stencil on'said wall, an inking chamber within said cylinder having a concentric cylinder formed with perforations, a slide between said wall and concentric cylinder and formed with perforations corresponding in position to said perforations of said concentric cylinder, a shaft within said concentric cylinder disposed longitudinal-1y thereof and having a crank fixed to its outer end, anoperative connection between said slide and shaft adapted when said shaft is rocked to shift the slide into position for opening and closing the perforations of said cylinder, and stops for limiting the movement of said crank.

In testimony whereof I hereunto afiix my signature.

' HERBERT BURKHOLDT. 

